feat: Add more variables for template (#1160)

Fixed #775

 - Add dep target-lexicon v0.12.7
 - Add `target-{family, arch, libc, vendor}` to
   `package.metadata.binstall`.

For `{universal, universal2}-apple-darwin`, the `target-arch` is set to
`universal`.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

crates/binstalk/src/helpers/target_triple.rs

@@ -0,0 +1,54 @@
+use std::{borrow::Cow, str::FromStr};
+
+use compact_str::{CompactString, ToCompactString};
+use target_lexicon::Triple;
+
+use crate::{errors::BinstallError, helpers::is_universal_macos};
+
+#[derive(Clone, Debug)]
+pub struct TargetTriple {
+    // TODO: Once https://github.com/bytecodealliance/target-lexicon/pull/90
+    // lands, consider replacing use of CompactString with `Cow<'_, str>`.
+    pub target_family: CompactString,
+    pub target_arch: CompactString,
+    pub target_libc: CompactString,
+    pub target_vendor: CompactString,
+}
+
+impl FromStr for TargetTriple {
+    type Err = BinstallError;
+
+    fn from_str(mut s: &str) -> Result<Self, Self::Err> {
+        let is_universal_macos = is_universal_macos(s);
+
+        if is_universal_macos {
+            s = "x86_64-apple-darwin";
+        }
+
+        let triple = Triple::from_str(s)?;
+
+        Ok(Self {
+            target_family: triple.operating_system.to_compact_string(),
+            target_arch: if is_universal_macos {
+                "universal".to_compact_string()
+            } else {
+                triple.architecture.to_compact_string()
+            },
+            target_libc: triple.environment.to_compact_string(),
+            target_vendor: triple.vendor.to_compact_string(),
+        })
+    }
+}
+
+impl leon::Values for TargetTriple {
+    fn get_value<'s>(&'s self, key: &str) -> Option<Cow<'s, str>> {
+        match key {
+            "target-family" => Some(Cow::Borrowed(&self.target_family)),
+            "target-arch" => Some(Cow::Borrowed(&self.target_arch)),
+            "target-libc" => Some(Cow::Borrowed(&self.target_libc)),
+            "target-vendor" => Some(Cow::Borrowed(&self.target_vendor)),
+
+            _ => None,
+        }
+    }
+}